Masking body parts underneath clothes and armor?
A way to do this is with a "Mask Modifier", simply create a vertex group and add weight to the vertices you want to keep visible. then on your object's modifiers, add the one named "Mask" and set the vertex group box to whatever name you called the one you just added the weight to, and voila! its now masked
:D!!!

Step 1:
Add vertex group and weight paint the parts you want to be visible



Step 2: Add "Mask" modifier and select the vertex group you just created, I named mine "Mask"



Step 3: Confirm that it was done properly (I changed the armor piece visibility from textured to wireframe to demonstrate this)





Hope that helps n.n!